<template>
    <!-- 商品分类导航 -->
    <div class="type-nav">
        <div class="container">
            <!-- 时间委派 -->
            <div @mouseleave="leaveIndex">
                <h2 class="all">全部商品分类</h2>
                <!-- 三级联动 -->
                <div class="sort">
                    <!-- 时间委派+编程导航 进行路由跳转 -->
                    <div class="all-sort-list2" @click="goSearch">
                        <div class="item" v-for="(c1, index) in categoryList" :key="c1.categoryId">
                            <h3 @mouseenter="changeIndex(index)" :class="{ cur: currentIndex == index }">
                                <a :data-categoryName="c1.categoryName" :data-category1Id="c1.categoryId">
                                    {{ c1.categoryName }}</a>
                            </h3>
                            <!-- 三级分类 -->
                            <div class="item-list clearfix"
                                :style="{ display: currentIndex == index ? 'block' : 'none' }">
                                <div class="subitem" v-for="(c2, index) in c1.categoryChild" :key="c2.categoryId">
                                    <dl class="fore">
                                        <dt>
                                            <a :data-categoryName="c2.categoryName" :data-category2Id="c2.categoryId">{{
                                                c2.categoryName }}</a>
                                        </dt>
                                        <dd>
                                            <em v-for="(c3, index) in c2.categoryChild" :key="c3.categoryId">
                                                <a :data-categoryName="c3.categoryName"
                                                    :data-category3Id="c3.categoryId">
                                                    {{ c3.categoryName }}</a>
                                            </em>
                                        </dd>
                                    </dl>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
            <nav class="nav">
                <a href="###">服装城</a>
                <a href="###">美妆馆</a>
                <a href="###">尚品汇超市</a>
                <a href="###">全球购</a>
                <a href="###">闪购</a>
                <a href="###">团购</a>
                <a href="###">有趣</a>
                <a href="###">秒杀</a>
            </nav>

        </div>
    </div>
</template>

<script>
import { mapState } from 'vuex'
// 防抖节流引入 把lodash全部引入，应该按需引入
import throttle from 'lodash/throttle'

export default {
    name: 'TypeNav',
    data() {
        return {
            currentIndex: -1
        }
    },
    // 组件挂载完毕，向服务器发送请求
    mounted() {
        this.$store.dispatch('categoryList')
    },
    computed: {
        ...mapState({
            // 右侧是函数，实用计算属性，立即执行
            categoryList: (state) => {
                return state.home.categoryList
            }
        })
    },
    methods: {
        changeIndex: throttle(function (index) {
            // 鼠标索引值
            this.currentIndex = index
        }, 50),
        // 鼠标移出
        leaveIndex() {
            this.currentIndex = -1
        },
        goSearch(event) {
            //event.target:获取到的是出发事件的元素(div、h3、a、em、dt、dl)
            let element = event.target;
            //给a标签添加自定义属性data-categoryName,全部的字标签当中只有a标签带有自定义属性，别的标签名字----dataset纯属扯淡
            let {
                categoryname, category1id, category2id, category3id,
            } = element.dataset;
            //第二个问题解决了：点击的到底是不是a标签（只要这个标签身上带有categoryname）一定是a标签
            //当前这个if语句：一定是a标签才会进入
            if (categoryname) {
                //准备路由跳转的参数对象
                let loction = { name: "search" };
                let query = { categoryName: categoryname };
                //一定是a标签：一级目录
                if (category1id) {
                    query.category1Id = category1id;
                    //一定是a标签：二级目录
                } else if (category2id) {
                    query.category2Id = category2id;
                    //一定是a标签：三级目录
                } else {
                    query.category3Id = category3id;
                }
                //判断：如果路由跳转的时候，带有params参数，捎带脚传递过去
                loction.params = this.$route.params;
                //动态给location配置对象添加query属性
                loction.query = query;
                //路由跳转
                this.$router.push(loction);
            }

        }
    },
}
</script>

<style lang="less">
.type-nav {
    border-bottom: 2px solid #e1251b;

    .container {
        width: 1200px;
        margin: 0 auto;
        display: flex;
        position: relative;

        .all {
            width: 210px;
            height: 45px;
            background-color: #e1251b;
            line-height: 45px;
            text-align: center;
            color: #fff;
            font-size: 14px;
            font-weight: bold;
        }

        .nav {
            a {
                height: 45px;
                margin: 0 22px;
                line-height: 45px;
                font-size: 16px;
                color: #333;
            }
        }

        .sort {
            position: absolute;
            left: 0;
            top: 45px;
            width: 210px;
            height: 461px;
            position: absolute;
            background: #fafafa;
            z-index: 999;

            .all-sort-list2 {
                .item {
                    h3 {
                        line-height: 30px;
                        font-size: 14px;
                        font-weight: 400;
                        overflow: hidden;
                        padding: 0 20px;
                        margin: 0;

                        a {
                            color: #333;
                        }
                    }

                    .item-list {
                        display: none;
                        position: absolute;
                        width: 734px;
                        min-height: 460px;
                        background: #f7f7f7;
                        left: 210px;
                        border: 1px solid #ddd;
                        top: 0;
                        z-index: 9999 !important;

                        .subitem {
                            float: left;
                            width: 650px;
                            padding: 0 4px 0 8px;

                            dl {
                                border-top: 1px solid #eee;
                                padding: 6px 0;
                                overflow: hidden;
                                zoom: 1;

                                &.fore {
                                    border-top: 0;
                                }

                                dt {
                                    float: left;
                                    width: 54px;
                                    line-height: 22px;
                                    text-align: right;
                                    padding: 3px 6px 0 0;
                                    font-weight: 700;
                                }

                                dd {
                                    float: left;
                                    width: 415px;
                                    padding: 3px 0 0;
                                    overflow: hidden;

                                    em {
                                        float: left;
                                        height: 14px;
                                        line-height: 14px;
                                        padding: 0 8px;
                                        margin-top: 5px;
                                        border-left: 1px solid #ccc;
                                    }
                                }
                            }
                        }
                    }

                    // &:hover {
                    //     .item-list {
                    //         display: block;
                    //     }
                    // }
                }

                .cur {
                    background: skyblue;
                }
            }
        }
    }
}
</style>